{"version":"2.1.299","anchor":"hidden-fast-mode-cli-override-helper","canonical_anchor":"hidden-fast-mode-cli-override-helper","heading":"New hidden --fast-mode option turns fast mode on or off at launch","tier":"use","area":"Models","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.299\/e\/hidden-fast-mode-cli-override-helper","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.299","markdown":"### New hidden `--fast-mode` option turns fast mode on or off at launch\n\nA new hidden `--fast-mode on` or `--fast-mode off` command-line option sets fast mode for a launch, unless `fastMode` is already set elsewhere\n\n**Unclear.** It is not clear which source supplies the `fastMode` value that overrides `--fast-mode`.\n\n**What**\n\nClaude Code has a new command-line option, `--fast-mode`, that you add when starting it. It accepts only two values, `on` and `off`; any other value is ignored. The option is hidden, so it does not appear in the help text.\n\nIf a `fastMode` value is already set somewhere else, that value wins and the option is ignored. Otherwise the option decides whether [fast mode](\/docs\/en\/fast-mode) is used.\n\n**Why**\n\nThis gives a way to choose fast mode for a single launch without changing settings, which is likely most useful for programs that start Claude Code themselves.\n\n- Area: Models\n- Tier: Use it now\n- Useful: 5\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}